1. Field of the Invention
The present invention relates to an unloader for a tire vulcanizer, which conveys a vulcanized tire from a tire vulcanizer to a post-cure inflator.
2. Related Background Art
Hitherto, when vulcanization molding of a green tire is completed in a tire vulcanizer, the vulcanized tire is dropped from an elevated spot and is moved to a post-cure inflator (hereinlater, abbreviated to a PCI) via an inclined conveyer by using self weight. After that, the vulcanized tire is contacted with a stopper of the PCI, thereby positioning the vulcanized tire to the center of the PCI.
According to the above method, however, the vulcanized tire and the center of the PCI are not positioned with high accuracy and the quality of the tire is lowered. In recent years, the vulcanized tire is moved from the tire vulcanizer to the PCI by an unloader for the tire vulcanizer.
The unloader (Japanese Patent Application Publication No. 3-67006) for a tire vulcanizer has a construction as shown in FIGS. 10 and 11. A guide rod 68 is vertically provided to a main frame 65 of a tire vulcanizer 61 via supporting members 66 and 67. A chuck boom 69 is provided to the guide rod 68 via bushings 72a and 72b so as to vertically and rotatably move. A chuck mechanism 70 is capable of holding a vulcanized tire 64 at the end of the chuck boom 69. According to the above construction, the vulcanized tire 64 can be conveyed from the tire vulcanizer 61 to a predetermined position of a PCI 62 by a turn around the guide rod 68 and linear motion along the guide rod 68. Therefore, by attaching the guide rod 68 with high precision, the vulcanized tire 64 can be positioned to the PCI 62 with high precision.
As shown in FIG. 12, in order to obtain a high-quality tire, the unloader for the tire vulcanizer is required to put the vulcanized tire 64 on a bottom rim 73 of the PCI 62 while positioning the tire 64 so as not to be deviated or inclined. In this instance, deviation and inclination of the vulcanized tire 64 for on the bottom rim 73 occurs since a chuck mechanism 70 is deviated and inclined relative to the vulcanized tire 64 when the chuck mechanism 70 holds the vulcanized tire 64 and separates the tire 64 from a mold 71. Therefore, the unloader for the tire vulcanizer is required to have high rigidity so that the chuck mechanism 70 can be accurately positioned and the vulcanized tire 64 is not deviated and inclined by a force which is applied when the vulcanized tire 64 is separated from the mold 71. Especially, when the unloader for the tire vulcanizer is operated at high speed in view of productivity, very high rigidity is required for the unloader for the tire vulcanizer.
However, as the above unloader for the tire vulcanizer, in the construction where the guide rod 68 supports the chuck mechanism 70 via the chuck boom 69, when the vulcanized tire 64 is separated from the mold 71, the guide rod 68 is deflected. There is, consequently, a problem in recent years that the rigidity corresponding to the higher quality of the tire and the improvement of the productivity cannot be obtained. There is another problem that the space between the main frame 65 and the PCI 62 is large by an amount corresponding to the space between the guide rod 68 and the main frame 65, thereby causing a large size of the whole tire vulcanizer.
Further, as the above unloader for the tire vulcanizer, in the construction where the bushings 72a and 72b are fit into the guide rod 68, clearance between the guide 68 and the bushings 72a and 72b is increased with time by abrasion of the bushings 72a and 72b, thereby causing a problem that the positioning accuracy of the chuck mechanism 70 quickly deteriorates.
According to the invention, there is provided an unloader for the tire vulcanizer in which the positioning accuracy of the chuck mechanism 70 can be improved by the high rigidity and can be maintained for a long time, and the whole tire vulcanizer can be miniaturized.
In order to achieve the objects, according to the invention, by vertically and horizontally moving a chuck mechanism, a vulcanized tire is conveyed from a tire vulcanizer to a post-cure inflator while being held by the chuck mechanism and is positioned to a predetermined position in the post-cure inflator.
According to the invention, there is provided an unloader for a tire vulcanizer, comprising: a linear motion guide rail which is vertically fixed to a main frame of the tire vulcanizer and has a plurality of raceway grooves; a slider in which balls rolling on the raceway grooves of the linear motion guide rail are assembled and is movably engaged with the linear motion guide rail; a movable carriage having the slider so as to elevate along the linear motion guide rail; a revolving suspension member which is provided on the movable carriage and has a revolving rod vertically supported by bearings; and a chuck boom which is provided to the revolving rod so as to be turnable in the horizontal direction and supports the chuck mechanism.
According to the invention, the chuck boom can be also fixed at a position between the tire vulcanizer and the post-cure inflator.
According to the invention, a revolving arm can be coupled to the chuck boom via the supporting rod and the revolving arm is pushed and pulled by an actuator for turning which is provided on the movable carriage, thereby turning the chuck boom.
The turn of the chuck boom can be adjusted by an amount of a horizontal movement of the actuator for turning for the movable carriage and/or a stroke amount of the actuator for turning.
According to the construction, the linear motion guide rail is fixed to the main frame and has consequently high rigidity. Even when the chuck mechanism is elevated and a large force is applied from the slider to deflect the linear motion guide rail, the linear motion guide rail is hardly deflected. No clearance occurs between the linear motion guide rail and the slider. Since the revolving rod for revolving the chuck boom is supported by bearings, the clearance between the revolving rod and the bearing is extremely small.
Therefore, the inclination of the chuck mechanism and the chuck boom due to the deflection and clearance is extremely reduced and the vulcanized tire can be loaded with high positioning accuracy. Since the coefficient of friction of the bearing is very small, the clearance between the revolving rod and the bearings is not increased by abrasion. The high positioning accuracy can be maintained for a long time.
Further, since the linear motion guide rail is fixed to the main frame and no space exists between the linear motion guide rail and the main frame, the interval between the main frame and the post-cure inflator is reduced and the whole tire vulcanizer can be miniaturized.
Since the chuck boom and the chuck mechanism can be fixed in a position between the tire vulcanizer and the post-cure inflator, the maintenance, check and the exchanging work of the mold can be easily performed.
Since one elevating base has two right and left elevating mechanisms and the revolving mechanisms, the unloader for the tire vulcanizer can be compactly constructed.
According to the invention, the revolving of the chuck boom can be easily adjusted by changing the moving amount in the horizontal direction of the actuator for the movable carriage and/or the stroke amount of the actuator.